Dual Phase Change Thermal Diodes for Enhanced Rectification Ratios: Theory and Experiment

Anton L. Cottrill, Song Wang, Albert Tianxiang Liu, Wen-Jun Wang, Michael S. Strano

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Thermal diodes are materials that allow for the preferential directional transport of heat and are highly promising devices for energy conservation, energy harvesting, and information processing applications. One form of a thermal diode consists of the junction between a phase change and phase invariant material, with rectification ratios that scale with the square root of the ratio of thermal conductivities of the two phases. In this work, the authors introduce and analyse the concept of a Dual Phase Change Thermal Diode (DPCTD) as the junction of two phase change materials with similar phase boundary temperatures but opposite temperature coefficients of thermal conductivity. Such systems possess a significantly enhanced optimal scaling of the rectification ratio as the square root of the product of the thermal conductivity ratios. Furthermore, the authors experimentally design and fabricate an ambient DPCTD enabled by the junction of an octadecane-impregnated polystyrene foam, polymerized using a high internal phase emulsion template (PFH-O) and a poly(N-isopropylacrylamide) (PNIPAM) aqueous solution. The DPCTD shows a significantly enhanced thermal rectification ratio both experimentally (2.6) and theoretically (2.6) as compared with ideal thermal diodes composed only of the constituent materials.
Original languageEnglish (US)
Pages (from-to)1702692
JournalAdvanced Energy Materials
Issue number11
StatePublished - Jan 15 2018
Externally publishedYes


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